The US Army, like many other military organizations, is interested in lengthening the life of its vehicles and vehicle components. Doing so not only reduces the need to purchase new equipment but also reduces the logistical effort needed to sustain vehicles in the field or in forward combat areas. A case in point is the ignition system for the Army's High Mobility Multipurpose Wheeled Vehicle, or HMMWV. Recently, the Army developed a control circuit that increases the life of glow plugs in the HMMWV's diesel engine. Very basically, the circuit operates by imposing a duty cycle on the glow plugs. The cycle controls the level and duration of electrical power sent to the glow plugs to effect engine ignition and provides for controlled delays between applications of electrical power to the plugs. In order to test glow plug life through repetitions of the duty cycle, it was necessary to develop a test mechanism that emulated the environment of the glow plugs, that allowed sensors to be easily mounted on the test apparatus, and that provided a quick, simple way to immediately detect a plug's failure to glow at the appropriate point in the duty cycle. That testing mechanism was developed and is the subject of this patent application.
The mechanism is also useful for testing diesel ignition systems on fielded vehicles generally to determine whether the system is functioning properly. The mechanism is easily built from commonly available materials and requires very little in terms of instrumentation. Also, the source of electrical power and pressurized water needed by the mechanism can be provided by the battery and water pump of an automotive vehicle. Consequently, the mechanism can be used in the field, and particularly can be used under conditions typical of those behind the lines in a combat zone.